1. Field of the Invention
The invention relates to a vacuum cleaner comprising an exchangeable filter arranged within a receiving area of a vacuum cleaner housing. The filter has a through opening through which a holding arm extends for fastening the filter. The holding arm is secured with its upper end on the vacuum cleaner housing or the vacuum cleaner motor. A fastening member for fastening the filter is detachably connectable to the lower end of the holding arm.
2. Description of the Related Art
In vacuum cleaners, in particular, industrial vacuum cleaners and central vacuum cleaning devices, comprising an exchangeable filter that is configured as a cartridge having a central through opening, a fastening device for the exchangeable filter is required. Customarily, a threaded rod is provided for this purpose that is connected with its upper end to the housing or vacuum cleaner motor and extends through the central through opening of the filter, wherein its lower end projects from the through opening. Onto the lower end of the threaded rod a securing plate is pushed that rests against the bottom side of the filter and is secured by means of a knurled nut or wing nut that is screwed onto the threaded rod. A disadvantage of this type of filter attachment is that the exchange of the filter is relatively cumbersome because the knurled nut or wing nut must be unscrewed for this purpose and, after insertion of the new filter, must again be screwed on.
For this reason, there are already filter attachments in use in which a bayonet closure is provided. For this purpose, a bayonet closure member is to be inserted into appropriate recesses at the lower end of the holding arm that penetrates the central through opening of the filter and is to be secured by turning it. In practice, it was found that the user not always complete the turning action required for completely securing the bayonet closure. This has the result that the filter is not reliably fastened and can become detached in operation of the vacuum cleaner. This causes dust to enter the vacuum cleaner motor leading to imbalance that reduces the service life of the vacuum cleaner motor.
Also known are clasp closures in which a clasp is mounted on the lower end of the holding arm that extends through the filter and projects from the through opening and spans the through opening of the filter, wherein the clasp rests against the lower lateral surface of the filter. In the case of such a clasp closure the exchange of the filter is also rather cumbersome.
Plug-in systems have also been proposed in which the filter is frictionally secured on a securing projection that projects from above into the central through opening. A disadvantage is that the risk of detachment of the filter during the course of operation of the vacuum cleaner cannot be reliably excluded.
Engagement elements, whose radial movement is blocked in a locking position of an actuating ring and whose radial movement is released in a release position of the actuating ring, are known in connection with coupling arrangements that form connecting devices for conduit sections of conduits for liquid or gaseous media or for conduits for conducting electric current or light. An example for a fluid coupling arrangement of this kind is disclosed in DE 199 15 291 A1. In such coupling devices, the medium to be conveyed passes through the two coupling parts to be connected to one another.